Parameterize Python plotting utilities in utils/python

utils/python/lib/plot_format.py

@@ -0,0 +1,55 @@
+"""
+ plot_format.py
+
+ Shared output-format helpers for the GNSS-SDR Python plotting utilities.
+
+ Provides a common --format command-line argument (same set of formats as
+ utils/skyplot/skyplot.py) and a matplotlib style that makes the vector
+ outputs (PDF/EPS) publication-ready with embedded fonts.
+
+ -----------------------------------------------------------------------------
+
+ GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
+ This file is part of GNSS-SDR.
+
+ Copyright (C) 2026  (see AUTHORS file for a list of contributors)
+ SPDX-License-Identifier: GPL-3.0-or-later
+
+ -----------------------------------------------------------------------------
+"""
+
+# Output formats offered by every plotting utility, matching the --format
+# option of utils/skyplot/skyplot.py. PNG is the default here.
+OUTPUT_FORMATS = ["png", "pdf", "eps", "svg", "jpg"]
+DEFAULT_OUTPUT_FORMAT = "png"
+
+
+def add_output_format_argument(parser):
+    """Add the shared --format option to an argparse parser."""
+    parser.add_argument(
+        "--format",
+        dest="output_format",
+        type=str.lower,
+        default=DEFAULT_OUTPUT_FORMAT,
+        choices=OUTPUT_FORMATS,
+        help="Saved figure format (default: png). Vector formats (pdf, eps, "
+        "svg) are written publication-ready with embedded fonts.",
+    )
+
+
+def apply_publication_style():
+    """Configure matplotlib so saved figures are publication-ready.
+
+    The key settings embed the fonts in PDF and EPS output (font type 42 =
+    TrueType) instead of leaving them as the default Type 3 fonts, which many
+    journals reject. SVG text is kept editable, and raster output uses a high
+    DPI. The active font family is left untouched, so plots keep their usual
+    look; whatever font is in use gets embedded.
+    """
+    import matplotlib.pyplot as plt
+
+    plt.rcParams["pdf.fonttype"] = 42  # embed TrueType fonts in PDF
+    plt.rcParams["ps.fonttype"] = 42  # embed TrueType fonts in EPS/PS
+    plt.rcParams["svg.fonttype"] = "none"  # keep SVG text editable
+    plt.rcParams["savefig.dpi"] = 300  # high-resolution png/jpg
+    plt.rcParams["savefig.bbox"] = "tight"  # trim surrounding whitespace